Expansible mandrels



ug. l5, i967 c. GUILD EXPANSIBLE MANDRELS I NVEN TOR. CHARLES L. GUILD 3 Sheets-Sheet l Filed May 14, 1964 ATTORNEY ,'Aug. 15, i967 I `@mmm I 3,335,574'

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INVENTOR CHARLES L. GUILD BY ug. 15, 1967 c. l.. GUILD 3,335,574

EXPANSIBLE MANDRELS Filed May 14, 1964 5 sheets-sheet s n V I l SIMM-lluvia E;

VVE/WUR: CHARLES 1 GUILD ATTH/VEY United States Patent C) 3,335,574 EXPANSIBLE MANDRELS Charles L. Guild, Rumford, RJ., assignor to Shell Oil Company, New York, NX., a corporation of Delaware Filed May 14, 1964, Ser. No. 367,500 4 Claims. (Cl. 61--53.72)

The present invention relates to expansible mandrels for insertion into and for driving engagement with a form for a cast-in-place pile.

Cast-in-place piles require that hollow forms be driven into the ground to the required depth. Such forms are, typically, thin-walled members such as light gauge pipes or corrugated shells each requiring that the driving means be capable of being freely entered therein and brought into secure engagement with the interior of the form in the lower part thereof and to be released from such engagement to enable the driving means to be withdrawn after the form has been driven.

Such means as are presently available for the driving of such forms have not proved to be wholly satisfactory in one or more of the following categories; cost and complexity, failure to provide a tight engagement with the form, and ease of operation, both as to driving engagement with the form and as to disengagement therefrom.

The principal objective of the present invention is to provide expansible mandrels that do not have such shortcomings as those to which general reference has been made. In accordance with that general objective, each expansible mandrel has a tubular members provided With external expansible encasement in a selected portion or portions of its form-entering end, the encasement being annularly secured to the tubular member in axially spaced zones against axial movement relative thereto, the cross sectional dimensions of the expansible mandrel being such that it is a free but close lit in the form when the eneasement is deflated and in tight driving contact therewith when inflated The encasement is in the form of a sleeve or a series of sleeves either arranged in abutting relationship or spaced from each other along the tubular member. The tubular member is provided with means for admitting air under pressure through its wall between the annular zones of attachment to expand the encasement to effect tight driving contact of the mandrel with the interior of the form after the mandrel has been entered therein.

One important objective of the invention is to provide such a mandrel with the expansible encasement being the mandrel element engageable with the interior of the form when the form is being driven and also such a mandrel with an outer tubular members having lengthwise slots in its form-entering end that establish sections to provide an expansible mandrel portion forced into driving engagement with the interior of the form when the encasement is inflated.

A particular objective of the invention is to provide an expansible mandrel in which the means interlocking the expansible encasement and the tubular member are cornplemental annular ribs and grooves with the preferred arrangement being one in which the tubular member has external, axially spaced annular grooves and the expansible encasement has internal, annular ribs axially spaced so that each is entrant of an appropriate one of the grooves. In practice, a clamp is provided that encircles the expansible encasement in each of the zones in which it is thus connected to the tubular member.

Another important objective of the invention is the provision of such mandrels whose expansible encasements include reinforcements in the annular zones of attachment to the tubular member, the reinforcements extending axially to such an extent that the margins thereof are in annular engagement with the form or the outer 3,335,574 y Patented Aug. l5, 1967 tubular member when the encasement is expanded for form driving.

Yet another objective of the invention is the provision of an internally chambered expansible mandrel with the internal chambering being connected to a suitable source of air under pressure and ported through the tubular member to admit air externally thereof between each two proximate axially spaced zones of attachment of the expansible encasement. The chambering may be in the form of an internal, rigid sleve secured at its ends to the interior of the tubular member or a series of such sleeves may be provided. Where the tubular member is itself sectioned, each section that is to have expansible encasement is provided with such internal chambering. Where there are a series of internal chambers, these may be interconnected in series.

In the accompanying drawings there are shown illustrative embodiments of the invention from which these and other objectives, novel features, and advantages will be readily apparent.

In the drawings:

FIGURE 1 is a side elevation of a mandrel in accordance with one embodiment of the invention, the mandrel being shown in elevation within a longitudinally sectioned form,

FIGURE 2 is a longitudinal, fragmentary -=section thereof on a substantially increased scale,

FIGURE 3 is a fragmentary section, on a further increased scale, the section being taken through a zone where an expansible sleeve is locked to a tubular member,

FIGURE 4 is a longitudinal, fragmentary section of the upper part of the tubular member, illustrating the internal support of the air conduit,

FIGURE 5 is a like view showing the support of the air conduit, the View being taken as if the tubular member were turned from its FIGURE 4 position,

FIGURE 6 is a longitudinal section illustrating a modifcation of the invention in which the mandrel member comprises interconnected sections,

FIGURE 7 is a fragmentary side elevation of the formentering expansible end portion of a mandrel in accordance with another embodiment of the invention,

FIGURE 8 is a fragmentary View of the expansible end portion with the outer tubular member longitudinally sectioned and attached to the inner tubular member above the expansible portion of the mandrel, and

FIGURE 9 is a development of the upper end of the outer mandrel portion.

A mandrel in accordance with the embodiment of the invention illustrated by FIGURES l-S is generally indicated at 10 and is shown as consisting of a tubular member 11 in the form of steel tubing of a length determined by the pile requirements of a particular job. A flange 12, for use in attaching the mandrel 10 to the driver, not shown, is welded to the upper end of the tubular member 11 and an end plate 13 is attached to its bottom end by cap screws 14.

As representative of a form for a cast-in-place pile, there is shown a length of corrugated tubing 1S provided with a cap 16 by which its earth-entering end is closed. The mandrel 10 is dimensioned to lit freely within the form 15. In order that, when the mandrel 10 is bottomed in the form 15 it may be connected in driving relation thereto, it includes expansible encasement which is generally indicated at 17 and shown as comprising a series of rubber ysleeves 18. |The use of a series of sleeves is preferred to a unitary casing because of the length of engagement between the mandrel and the form that is necessary. In practice, sleeves 18, in the approximate range of from four to live feet in length are used, with three such sleeves being shown as located at the bottom end of the mandrel 10 with their ends abutting. These may be spaced from each other, if desi-red, and any number of additional sleeves 18 may be used either as spaced series or otherwise.

Each sleeve 18 must be securely connected to the tubular member 11 in axially spaced annular zones and, to that end, each sleeve has a plurality of anchoring portions, the end anchoring portions 18A and the intermediate anchoring portions 18B. Each anchoring portion is in the form of an annular rib and the ribs are spaced so that each may enter into an appropriate one of the external, axially spaced, annular grooves 19 with which the tubular mem-ber 11 is provided. Each anchoring portion of each sleeve 18 is also encircled by adjustable clamping straps 20 and preferably these are used with an interposed collar 21 having inturned edges 21A.

An internal lsleeve 22, typically a steel tube, has its ends welded to annular seats 23 on the interior of the tubular member 11 and is substantially -coextensive with the series of sleeves 18 to provide internal chambering. Adjacent the upper end of the mandrel there is a titting 24, see FIGURE 4, to enable an air conduit, not shown, from any suitable source of air -under pressure to be attached to the mandrel. Secured -to the fitting 24 within the tubular member 11 there is an elbow 25 to which is connected the fitting 26 at the upper end of a length of hose 27. The lower end of the hose 27, see FIG- URE 2, is provided with a fitting 28 attached to an elbow 29 connected to a itting 30 opening through the lower seat 23 and the lower end of the internal sleeve 22. The tubular member 11 is provided with a series of holes 31, there being one such hole opening between each two adjacent annular, anchoring portions of each sleeve 18. In practice, there is a substantial length of hose 27 and to relieve the fittings of the weight thereof, the hose is passed through a sleeve 32, see FIGURES 4 and 5, of the type that grip tightly on a lengthwise pull, the sleeve 32 being `supported by hangers 33 on the interior of the tubular member 11.

From the foregoing, yit will be apparent that, by admitting air under pressure into the mandrel 1i), the sleeve 13 will be expanded into tight contact with the interior surfaces of the form 15, a connection that is particularly effective when the form is of a corrugated type. It is advantageous to provide reinforcement where the sleeves 13 are not backed by the form 15 during use of the mandrel. In practice, such reinforcement is provided by making each sleeve thicker adjacent the Zones where it s annularly anchored, see FIGURES 2 and 3, the thickness being indicated at 18C and extending axially a sufficient distance so that its margin or margins extend in the area where the sleeve is backed by the form 15.

In FIGURE 6, there is shown an embodiment of the invention in which the tubular member of a mandrel is established by a series of tubular sec-tions 34 each having inwardly tapering end sections 35 termin-ating in anged end portions 36 shown -as detachably bolted together. While both of the sections 34 shown in FIGURE 6 4a re grooved as at 37 for the reception of sleeve anchoring ribs, similar tubular sections may be used simply as spacer and the length of the section 34 may be varied depending on the length of expansible encase-ment with which it i-s to be provided. Eac-h section 34 has an internal sleeve 38 whose ends are mounted by seats 39 secured within the section 37 to provid-e an internal chamber and these may be connected in series as by -a length of hose 40 connected to iittings 41 and 42, the former at the lower end of an upper `section and the latte-r at the upper end of the lower section.

In the embodiment of the invention illustrated by FIG- URES 7-9, a mandrel, generally indicated at 43, is shown as consisting of an inner tubular member 44 and a generally indicated outer tubular 4member 45 both of which may be steel tubing.

The outside diameter of the tubular member 45 is such that it is a close but ree tit in the pile form 46 which is shown as of the corrugated tubing type having an end cap 47. The form-entering end of the tubular member 45 is divided into three sections 45A, 45B, and 45C by lengthwise, open-ended slots 48 of su'icient length to provide an expansible mandrel end portion capable of tightly holding the pile form 46 while it is being driven. A spring clip 49 encircles the sections 45A, 45B, and 45C close to their free ends to yieldably hold them in their inner, form-entering positions.

The corrugations 46A of the pile form 46 are helical and the sections 45A, 45B, and 45C are provided with driving lugs 50 'm the form of Ihalf-round bars welded thereto along helical parts appropriate for entry into and engagement with the corrugations 46A of the pile form. The number of helical lugs may be decreased, as shown, in the upper part of the expansible portion of the tubular member 45.

rIhe tubular member 44 is a free fit within the expansible portion of the tubular member 45 and an end plate 51 is attached to its free end, the diameter of the plate 51 being such that it normally overlies the ends of the Isections 45A, 45B, `and 45C but is itself a free t within the pile form 46. The tubular member 44 has an upper portion 52 iitting the tubular member 45 and welded thereto as through welding slots 53 and an intermediate inwardly and downwardly tapering portion 54. The upper portion 52 is of whatever length is required for driving a particular pile form.

The tubular member 44 is provided with an encasement ysimilar to that detailed in connection with the embodiment of the invention illustrated by FIGURES l-5. The encasement consists of a series of sleeves 55, similar to the Isleeves 18, and clamped by clamping straps 56 to the 4tubular member 44 in axially spaced zones. The sleeves 55 have reinforcements 57 in the Zone of the clamping straps 56 each extending marginally thereof to engage with the tubular member 45 when expanded by the admission of air through the wall of the tubular member 44, the air delivery means lbeing similar to the air delivery means shown in FIGURES 1 5. It will also be noted that the sleeves 55 have spaced, inwardly disposed annular 'ribs 58 entered in annular channels 59 with which the tubular member 44 is provided.

From the foregoing, it will be appreciated that expansible mandrels in accordance with the invention `are well adapted to meet operating requirements since their encasernents are defined by expansible sleeves securely locked to the tubular member 11 or 4S at a plurality of axially spaced zones.

I claim:

1. In an expansible mandrel for insertion into and for driving an earth entering, corrugated form for a cast-inplace pile, a tubular backing member having at least two .axially spaced, annular channels, an expansible sleeve overlying said channels and including internally projecting annular shoulders, one for each channel and entrant thereof, annular backing means locking said sleeve to said backing member in each of said channels, and means to deliver air under pressure through said backing member between each two channels, thereby to innate said sleeve, the cross sectional dimensions of the mandrel, when said sleeve is deiiated, being such that the mandrel is a free but close fit Within said form, and said mandrel being thin enough to deform against and in conformity with the corrugation of the form to insure tight driving contact with said form when said sleeve is inflated, and portions of said sleeve adjacent each shoulder being of such increased thickness and of such axial extent as to engage the form when said sleeve is thus inflated and to resist axial distortion in response to the inflating pressure.

2. The mandrel of claim 1, in which there is a series of annular channels, the expansible sleeve is divided into axially spaced sections by the locking means, and the air delivery means includes a second tubular member within the backing member and so dimensioned and `connected to the backing member as to establish an annular space of suicient axial extent to underlie the sections of the expansible sleeve, and the backing member has la series of ports, one for each sleeve section and effecting communication With the interior thereof.

3. In an expansib'le mandrel for insertion into and for driving an earth entering form for a cast-in-place pile, a tubular backing member including a form entering end of reduced diameter having at least two axially spaced, annular channels, an expansible sleeve overlying said channels and including internally projecting annular shoulders, one for each channel and entrant thereof, annular backing means backing said sleeve to said backing member in each of said channels, and means to deliver air under pressure through said backing member between each two channels, thereby to inate said sleeve, a second tubular member secured to said backing member beyond the reduced diameter end thereof and defining with said end an annular space accommodating the sleeve when deated, said second tubular member overlying the entire length of said reduced diameter end and including circumferentially spaced arcuate sections idening longitudinally extending, open ended slots, the cross sectional dimensions of the mandrel, when said sleeve is deflated, being such that the mandrel is a free but close t Within said form, and said mandrel being in tight driving contact with said form when said sleeve is inflated.

4. The mandrel of claim 3 and an end plate xed on the form entering end of the rst tubular member.

References Cited UNITED STATES PATENTS 2,334,386 11/1943 Cortella 61-53.72 2,625,338 1/1953 McArn 242-72 2,869,329 1/ 1959 Jourdain. 2,876,961 3/1959 Cole et al 242-72 2,881,593 4/1959 Cobi 61-5372 3,041,839 7/1962 Kupka 61 53.72

FOREIGN PATENTS 163,738 1955 Australia. 703,654 2/1954 Great Britain.

DAVID J. WILLIAMOWSKY, Primary Examiner. JACOB SHAPIRO, Examiner. 

1. IN AN EXPANSIBLE MANDREL FOR INSERTION AND FOR DRIVING AN EARTH ENTERING, CORRUGATED FORM FOR A CAST-INPLACE PILE, A TUBULAR BACKING MEMBER HAVING AT LEAST TWO AXIALLY SPACED, ANNULAR CHANNELS, AN EXPANSIBLE SLEEVE OVERLYING SAID CHANNELS AND INCLUDING INTERNALLY PROJECTING ANNULAR SHOULDERS, ONE FOR EACH CHANNEL AND ENTRANT THEREOF, ANNULAR BACKING MEANS LOCKING SAID SLEEVE TO SAID BACKING MEMBER IN EACH OF SAID CHANNELS, AND MEANS TO DELIVER AIR UNDER PRESSURE TH ROUGH SAID BACKING MEMBER BETWEEN EACH TWO CHANNELS, THEREBY TO INFLATE SAID SLEEVE, THE CROSS SECTIONAL DIMENSIONS OF THE MANDREL, WHEN SAID SLEEVE IS DEFLATED, BEING SUCH THAT THE MANDREL IS A FREE BUT 